What do yo make of these Leycesteria flower spikes?

This a nice version, are you asking why it is like this? if so here goes:
the seeds always have a mix of genetic information [genes] and clearly the genes for colour and flower form have been mixed differently. the result is as you see.

I have the white one down as L. formosa alba, obviously, but I wondered if anyone grew any of the other forms or species before I do anything about this variation. Oddly enough all the plants I grew from this lot of seed seem to be this green bracted variation, which is what got me wondering if it was not formosa at all. Ever other time I have grown L. formosa from seed it has grown as the standard red/purple bracted form.

but mother nature as she is, could throw up a mutation to kick start change. There may be another closely related plant in the neighbourhood that has provided the pollen for this form.

There are 5 or 6 other species which are mentioned in various places, but the only descriptions of them I can find are in Latin. Now my Botanical latin is not really up to that, sadly. I can say it is not Ll. crocothrysos as that is yellow, gracilis because the leaves are long and thin, gluaucophylla because that has blur/grey powdery leaves. That leaves stipitata and sinensis (I think) to find out about.
The place the seed came from could have anyone of those growing as it is well known for its plant collections.

well i think you may an exciting hybrid then owdb. certainly worth doing a check with the RHS. you can send them plant material for identification